Substrate processing method, semiconductor chip manufacturing method, and resin-adhesive-layer-backed semiconductor chip manufacturing method

ABSTRACT

To provide a substrate processing method and a semiconductor chip manufacturing method that enable low-cost formation of a mask for etching using plasma etching. During formation of a mask used in plasma dicing for separating a semiconductor wafer  1  into discrete semiconductor chips  1   e  by means of etching using plasma processing, there is adopted a method including printing a lyophobic liquid in an area on a rear surface  1   b  that is to be an objective of etching, thereby forming a lyophobic pattern made up of lyophobic films  3 ; supplying a low viscosity resin  4   a  and a high viscosity resin  4   b , in this sequence, to the rear surface  1   b  on which the lyophobic pattern is formed, thereby forming a resin film  4  that is thicker than the lyophobic films  3  in an area where the lyophobic films  3  are not present; and curing the resin film  4 , to thus form a mask  4 * that covers an area except for the area to be etched. Thus, a mask for etching purpose can be formed at low cost without use of a high-cost method, like photolithography.

TECHNICAL FIELD

The present invention relates to a substrate processing method forpartially eliminating a substrate, like a semiconductor wafer, asemiconductor chip manufacturing method to which the substrateprocessing method is applied, and a resin-adhesive-layer-backedsemiconductor chip manufacturing method.

BACKGROUND ART

A semiconductor device to be mounted on a substrate of electronicequipment is manufactured by means of slicing into pieces asemiconductor chip made up of discrete semiconductor devices from asemiconductor wafer, wherein integrated circuits are fabricated in therespective discrete semiconductor devices in a wafer state. With arecent increase in the degree of difficulty in handling a semiconductorchip resultant from a decrease in thickness of the semiconductor chip,there has been proposed plasma dicing for dicing a semiconductor waferinto pieces of semiconductor chips by means of plasma etching.

Plasma dicing is to etch a semiconductor wafer by means of plasma whilethe semiconductor wafer except for scribe lines showing grid-shapedsplit positions is masked by means of a resist film, thereby cutting thesemiconductor wafer along the scribe lines. Therefore, plasma dicingrequires a step of making a mask over the semiconductor wafer. A maskhas heretofore been made by means of a photolithography (see PatentDocument 1) for transferring a scribe line pattern by use of aphotosensitive material or a method (see Patent Document 2) foreliminating a scribe line area on a mask layer formed over a surface ofa semiconductor wafer by irradiation of a laser beam to thereby make amask.

RELATED ART DOCUMENT Patent Documents

-   Patent Document 1: JP-A-2004-172364-   Patent Document 2: JP-A-2005-191039

DISCLOSURE OF THE INVENTION Problem that the Invention is to Solve

However, the foregoing related art examples encounter a problem of maskformation involving consumption of high cost. Specifically, thephotolithography technique is originally intended for a high precisionpattern, such as an integrated circuit and requires complicate steps andexpensive facilities, which inevitably entails a cost rise. Forming amask by use of a laser beam entails facility cost for laser beamirradiation, which poses difficulty in forming a mask at low cost. Theproblems pertaining to mask formation are not limited solely to plasmadicing and are also true for various processing operations utilizing anapplication of plasma etching; for instance, processing for making viaholes in a substrate, processing intended for a substrate for use with aMEMS (Microelectromechanical System), and a substrate processing methodfor fabricating integrated circuits on a transparent display panel, andthe like.

Accordingly, the present invention aims at providing a substrateprocessing method that enables inexpensive formation of a mask foretching using plasma processing, a semiconductor chip manufacturingmethod utilizing an application of the substrate processing method, anda resin-adhesive-layer-backed semiconductor chip manufacturing method.

Means for Solving the Problem

A substrate processing method of the present invention is directedtoward a substrate processing method for partially eliminating asubstrate by etching using plasma processing, the method comprising:

a lyophobic pattern formation step of printing a lyophobic liquid to anarea to be etched away on a processing target surface of the substrate,thereby forming a lyophobic pattern;

a resin film formation step of preparing two types of liquids, or afirst liquid including at least a solvent and a resin and a secondliquid whose viscosity is lower than a viscosity of the first liquid andsupplying the liquids in descending sequence of the second liquid andthe first liquid to the processing target surface of the substrate onwhich the lyophobic pattern is formed, thereby forming a resin film thatis thicker than the lyophobic pattern in an area where the lyophobicpattern is not formed;

a mask formation step of curing the resin film, to thus form on theprocessing target surface a mask for covering an area except for thearea to be etched away;

a lyophobic pattern removal step of removing the lyophobic pattern fromthe processing target surface after performance of processing pertainingto the mask formation step;

an etching step of etching the substrate from the processing targetsurface thereof using plasma processing after processing pertaining tothe lyophobic pattern removal step; and

-   -   a mask removal step of removing the mask from the processing        target surface after completion of processing pertaining to the        etching step.

A semiconductor chip manufacturing method of the present invention isdirected toward a semiconductor chip manufacturing method for separatinga semiconductor wafer, which has a plurality of semiconductor devices ona circuit fabrication surface and which is affixed with a protectivesheet for protecting the circuit fabrication surface by means of etchingusing plasma processing, into semiconductor chips made up of respectivesemiconductor devices, the method comprising:

a lyophobic pattern formation step of printing a lyophobic liquid onscribe lines serving as borders between semiconductor chips on aprocessing target surface of the semiconductor wafer that is anotherside of the circuit fabrication surface, thereby forming a lyophobicpattern;

a resin film formation step of preparing two types of liquids, or afirst liquid including at least a solvent and a resin and a secondliquid whose viscosity is lower than a viscosity of the first liquid andsupplying the liquids in descending sequence of the second liquid andthe first liquid to the processing target surface of the substrate onwhich the lyophobic pattern is formed, thereby forming a resin film thatis thicker than the lyophobic pattern in an area where the lyophobicpattern is not formed;

a mask formation step of curing the resin film, to thus form on theprocessing target surface a mask for covering an area except for thearea to be etched away;

a lyophobic pattern removal step of removing the lyophobic pattern fromthe processing target surface after performance of processing pertainingto the mask formation step;

an etching step of etching the semiconductor wafer from the processingtarget surface thereof until the protective sheet becomes exposed on theprocessing target surface, after processing pertaining to the lyophobicpattern removal step; and

a mask removal step of removing the mask from the processing targetsurface after completion of processing pertaining to the etching step.

A resin-adhesive-layer-backed semiconductor chip manufacturing method isdirected toward a resin-adhesive-layer-backed semiconductor chipmanufacturing method for manufacturing semiconductor chips having onrear surfaces resin adhesive layers for die-bonding purpose by means ofplasma dicing for separating a semiconductor wafer, which has aplurality of semiconductor devices on a circuit fabrication surface andwhich is affixed with a protective sheet for protecting the circuitfabrication surface, into respective semiconductor devices by means ofetching using plasma processing, the method comprising:

a lyophobic pattern formation step of printing a lyophobic liquid onscribe lines serving as borders between semiconductor chips on a rearsurface that is another side of the circuit fabrication surface of thesemiconductor wafer, thereby forming a lyophobic pattern;

a resin film formation step of preparing two types of liquids, or afirst liquid including at least a solvent and a resin and a secondliquid whose viscosity is lower than a viscosity of the first liquid andsupplying the liquids in descending sequence of the second liquid andthe first liquid to the processing target surface of the substrate onwhich the lyophobic pattern is formed, thereby forming a resin film thatis thicker than the lyophobic pattern in an area where the lyophobicpattern is not formed;

a resin adhesive layer formation step of semi-curing the resin film, tothus form a resin adhesive layer;

a lyophobic pattern removal step of removing the lyophobic pattern fromthe rear surface after performance of processing pertaining to the resinadhesive layer formation step; and

an etching step of etching, after performance of processing pertainingto the lyophobic pattern removal step, the semiconductor wafer from therear surface thereof while the resin adhesive layer is taken as a maskuntil the protective sheet becomes exposed on the rear surface.

Advantages of the Invention

According to the present invention, during mask formation implemented byetching using plasma processing, there is adopted a method includingprinting a lyophobic liquid in an area to be etched on the processingtarget surface, thereby forming the lyophobic pattern; preparing twotypes of liquids; namely, the first liquid including at least a solventand a resin, and the second liquid whose viscosity is lower than that ofthe first liquid; supplying the liquids, in descending sequence of thesecond liquid and the first liquid, to the processing target surface ofthe substrate over which the lyophobic pattern is already formed, tothus form the resin film that is thicker than the lyophobic pattern onthe area where the lyophobic pattern is not formed; and curing the resinfilm, to thus form a mask that covers an area of the semiconductor waferexcept the area to be etched. Thus, a mask for etching using plasmaprocessing can be formed at low cost without use of a high-cost method,like photolithography.

Further, according to the present invention, during manufacture ofsemiconductor chips for separating a semiconductor wafer intosemiconductor chips formed from respective semiconductor devices bymeans of etching using plasma processing, there is adopted a methodincluding printing a lyophobic liquid in an area to be etched on aprocessing target surface, thereby forming the lyophobic pattern;preparing two types of liquids; namely, the first liquid including atleast a solvent and a resin, and the second liquid whose viscosity islower than that of the first liquid; supplying the liquids, indescending sequence of the second liquid and the first liquid, to theprocessing target surface of the semiconductor wafer over which thelyophobic pattern is already formed, to thus form the resin film that isthicker than the lyophobic pattern on the area where the lyophobicpattern is not formed; and curing the resin film, to thus form a maskthat covers an area of the semiconductor wafer except the area to beetched. Thus, a mask for etching using plasma processing is formed atlow cost, so that semiconductor chips can be manufactured at low cost.

Moreover, according to the present invention, during manufacture ofsemiconductor chips for separating a semiconductor wafer intosemiconductor chips with resin adhesive layers formed from respectivesemiconductor devices by means of etching using plasma processing, thereis adopted a method including printing a lyophobic liquid on scribelines, which are borders between semiconductor chips, on a rear surfacethat is another side of a circuit fabrication surface of thesemiconductor wafer, thereby forming the lyophobic pattern; preparingtwo types of liquids; namely, the first liquid including at least asolvent and a resin, and the second liquid whose viscosity is lower thanthat of the first liquid; supplying the liquids, in descending sequenceof the second liquid and the first liquid, to the processing targetsurface of the semiconductor wafer over which the lyophobic pattern isalready formed, to thus form the resin film that is thicker than thelyophobic pattern on the area where the lyophobic pattern is not formed;semi-curing the resin film, to thus form a resin adhesive layer; andetching the rear surface of the semiconductor wafer while the resinadhesive layer is taken as a mask after removal of the lyophobic patternfrom the rear surface. Thus, a mask for etching using plasma processingis formed at low cost, and the mask can be used as the resin adhesivelayer for die-bonding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart showing a semiconductor chip manufacturing methodutilizing an application of a substrate processing method of a firstembodiment of the present invention.

FIGS. 2 (a) to (g) are explanatory process charts of the semiconductorchip manufacturing method and a semiconductor chip boding method thatutilize the application of the substrate processing method of the firstembodiment of the present invention.

FIGS. 3 (a) to (d) are explanatory process charts of the semiconductorchip manufacturing method and the semiconductor chip boding method thatutilize the application of the substrate processing method of the firstembodiment of the present invention.

FIG. 4 is a plan view of a semiconductor wafer that is an object of thesubstrate processing method of the first embodiment of the presentinvention.

FIG. 5 is a plan view of the semiconductor wafer that is an object ofthe substrate processing method of the first embodiment of the presentinvention.

FIG. 6 is an enlarged view of a lyophobic pattern of the substrateprocessing method of the first embodiment of the present invention.

FIG. 7 is an enlarged cross sectional view of the semiconductor waferthat is to be an object of the substrate processing method of the firstembodiment of the present invention.

FIGS. 8 (a) to (c) are explanatory views of resin coating performed formaking a mask under the substrate processing method of the firstembodiment of the present invention.

FIG. 9 is an enlarged view showing a liquid resin and the lyophobicpattern employed in the substrate processing method of the firstembodiment of the present invention.

FIG. 10 is a cross sectional view of a resin layer and a mask of thesubstrate processing method of the first embodiment of the presentinvention.

FIG. 11 is a flowchart showing a resin-adhesive-layer-backedsemiconductor chip manufacturing method of a second embodiment of thepresent invention.

FIGS. 12 (a) to (f) are explanatory process charts of theresin-adhesive-layer-backed semiconductor chip manufacturing method anda method for bonding a semiconductor chip with a resin adhesive layer ofthe second embodiment of the present invention.

FIGS. 13 (a) to (d) are explanatory process charts of theresin-adhesive-layer-backed semiconductor chip manufacturing method andthe method for bonding a semiconductor chip with a resin adhesive layerof the second embodiment of the present invention.

FIG. 14 is an enlarged view of a lyophobic pattern of theresin-adhesive-layer-backed semiconductor chip manufacturing method ofthe second embodiment of the present invention.

FIG. 15 is an enlarged cross sectional view of a semiconductor waferthat is to become an object of plasma dicing of the semiconductor chipwith a second resin adhesive layer manufacturing method of the secondembodiment of the present invention.

EMBODIMENTS FOR IMPLEMENTING THE INVENTION First Embodiment

First, a lyophobic pattern and a mask of the present embodiment aredescribed. In the present embodiment, during mask formation that isperformed at the occasion of etching utilizing plasma processing forseparating a semiconductor wafer, a lyophobic pattern is formed by meansof a resin (a lyophobic agent) that exhibits a lyophobic property withrespect to a solvent included in a liquid resin that is to work as amaterial making up a mask. Specifically, a lyophobic pattern is formedin advance over an area of the semiconductor wafer, except for an areawhere a mask is to be made, by use of the lyophobic agent. A liquidresin that makes a mask is caused to adhere to only the area where themask is to be made. On the occasion of formation of the lyophobicpattern, a liquid (a lyophobic liquid) made by dissolving the lyophobicagent in a solvent is printed in a predetermined pattern by means oftransfer printing, screen printing, dispensing, inkjet printing, or thelike. A solvent component is volatized after printing, whereupon thelyophobic pattern is completed.

A resin (resist) that will not be eliminated by a fluorine-based gasplasma and that is easily removed (ashed) by means of oxygen or anoxygen-contained gas plasma is used as a material making up the mask.Hydrocarbon-based resins have been used as resins exhibiting theseproperties. On the occasion of mask formation, a liquid resin made bydissolving a resist in a solvent is applied over a processing targetsurface of a substrate over which the lyophobic pattern has been formed,by means of a method like dispensing, inkjet printing, and spin coating.Since the lyophobic agent repels the solvent of the liquid resin appliedover the processing target surface, the liquid resin spreads over onlyan area of the processing target surface except for the lyophobicpattern. The solvent of the liquid resin is volatized in a baking step,thereby letting the resist adhere the processing target surface. A maskpatterned by the lyophobic pattern is thereby completed.

The present invention adopting such a mask formation method involves arequirement that the lyophobic agent used for making the lyophobicpattern be a combination exhibiting a lyophobic property with respect tothe solvent included in the liquid resin used for mask formation. Inaddition, a solvent capable of blending with a resin that is to serve asa resist must be chosen as a solvent. In general, two types of chemicalshave properties of easily blending with each other as SP values(solubility parameters) of the respective chemicals are more analogousto each other and repelling each other as the SP values increasinglydiffer from each other. Therefore, when the resist to be used is any ofthe hydrocarbon-based resins (having an SP value of 7.0 to 8.0), any ofsaturated-hydrocarbon-based solvents having an SP value of 7.0 to 8.0 ischosen as a solvent.

In relation to a choice of a lyophobic agent and a solvent used with aliquid resin, there are chosen substances corresponding to a combinationof substances having different SP values, preferably a combination ofsubstances whose SP values differ from each other by a value of 1.0 ormore. Therefore, if the solvent is any of saturated-hydrocarbon-basedsolvents (having an SP value of 7.0 to 8.0), any of acrylic resins(having an SP value of 9.2) or fluorine-based resins (having an SP valueof 3.6) can be used as a lyophobic agent. Further, when any ofsaturated-hydrocarbon-based solvents having an SP value of 8.0 is used,a silicone-based resin (having an SP value of 7.0) can be used as alyophobic agent. As mentioned above, a substance whose SP value differsfrom an SP value of the solvent used for a liquid resin by a value of1.0 or more is used as a lyophobic agent, whereby a liquid resin usedfor mask formation can be easily arranged on the processing targetsurface except for the lyophobic pattern.

Mask formation using the lyophobic pattern requires a uniform supply ofa liquid resin over the area of the processing target surface surroundedby the lyophobic pattern without occurrence of a two-dimensional gap ona border between the lyophobic pattern and the area. However, mereapplication of a liquid resin causes a problem caused by a viscosity ofthe liquid resin, such as that described below, which poses a difficultyin forming a mask having a good shape. Specifically, when the viscosityof the liquid resin is high, a supplied liquid resin attempts to gathertogether into as simple a shape as possible because of surface tension.For this reason, the liquid resin hardly enters an indentation of acorner on the processing target surface where the lyophobic pattern hasa cross. A two-dimensional void that is not supplied with a resin tendsto occur in only the indentation.

On the contrary, when the viscosity of the liquid resin is low, theresin easily spreads in a wet fashion over the processing target surfacewhen supplied in a liquid state. However, during a stage where thesolvent component of the resin evaporates, to thus cure the resin, theresin cannot maintain a desirable mask shape. Specifically, since aconcentration of a solid resin component of the liquid resin whoseviscosity is set to a low level is low, the resin changes in the courseof evaporation of the solvent in such a way that a two-dimensional shapeas well as a thicknesswise shape of the resin contract. For this reason,in a state where the liquid resin is supplied by application, the resinremains uniformly spread in a wet fashion over the area surrounded bythe lyophobic pattern. However, when the resin becomes cured as a resultof evaporation of the solvent, the two-dimensional shape of the resinbecomes contracted. Therefore, a two-dimensional void devoid of a resinoccurs on the border between the lyophobic pattern and the area in thesame way as mentioned previously.

Such a failure in the shape of the mask attributable to the viscosity ofthe liquid resin is ascribable to surface tension of the resin when theresin has a high viscosity and contractive deformation resultant fromevaporation of the solvent when the resin has a low viscosity.Therefore, it is extremely difficult to determine an appropriateviscosity range that enables prevention of occurrence of such a failurein shape. Accordingly, in the present embodiment, two types of liquidshaving different viscosity levels are prepared in a process of a maskbeing formed from a liquid resin as will be described below, and theliquids are supplied in two steps. Specifically, prior to supplying ahigh viscosity resin (a first liquid) including a resin component, whichis to make a mask, in a high concentration, a low viscosity resin (asecond liquid) that exhibits a viscosity lower than that of the highviscosity resin is first supplied. The low viscosity resin is thuscaused to spread uniformly in a wet fashion within an area surrounded bythe lyophobic pattern. Next, the high viscosity resin is supplied, tothus assure a quantity of resin component required to form a mask.

The substrate processing method is now described by reference to theflowchart of FIG. 1 and explanatory process charts of FIGS. 2 and 3. Thesubstrate processing method is to partially eliminate a material makingup the substrate through performance of etching using plasma processing.Plasma dicing is hereinbelow provided as example substrate processing;in other words, a semiconductor wafer separated into a plurality ofsemiconductor devices by means of scribe lines is taken as a substrate,and the scribe lines are partially eliminated by means of etching usinga plasma, thereby separating the semiconductor wafer into discretesemiconductor chips. The first embodiment, in a word, shows asemiconductor chip manufacturing method for separating a semiconductorwafer, which has a plurality of semiconductor devices on a circuitfabrication surface and a protective sheet for protecting the circuitfabrication surface affixed to the circuit fabrication surface, intosemiconductor chips made up of respective semiconductor devices, bymeans of etching using plasma processing.

In FIG. 1, a lyophobic pattern is first made over a semiconductor wafer1 serving as a substrate (ST1). As shown in FIG. 2( a), a plurality ofsemiconductor chips including integrated circuits (semiconductordevices) are fabricated on the semiconductor wafer 1. A protective sheet2 for protecting the integrated circuits is affixed to a circuitfabrication surface 1 a of the semiconductor wafer 1 where theintegrated circuits are fabricated. A rear surface 1 b that is the otherside of the circuit fabrication surface 1 a is made thin to a thicknessof 100 micrometers or less by means of removing a surface layer in athinning step, which is a preceding step, through performance ofmechanical grinding.

Next, as shown in FIG. 2( b), a lyophobic pattern is formed, on the rearsurface 1 b (corresponding to the processing target surface of thesubstrate to be etched) of the semiconductor wafer 1, along grid lines(corresponding to areas to be etched away) corresponding to scribe lines1 c (see FIG. 4) that separate the semiconductor wafer 1 into respectivesemiconductor chips 1 e and along a contour [see FIG. 2( a) and alyophobic film 3 e shown in FIG. 5] set to a predetermined width alongan outer edge of the semiconductor wafer 1 (a lyophobic patternformation step). In addition to being formed along the grid linescorresponding to the scribe lines 1 c (see FIG. 4), the lyophobicpattern is formed along the contour of the outer edge of thesemiconductor wafer 1. The lyophobic pattern formed along the contour isintended to prevent the liquid resin from running over the outer edge ofthe semiconductor wafer 1 to thereby fall from the wafer, which wouldotherwise occur when the liquid resin is applied after formation of thelyophobic pattern. The lyophobic pattern formation step includes a printstep of printing a lyophobic liquid in a predetermined pattern on theprocessing target surface and a baking step of letting a solventcomponent of the printed lyophobic liquid evaporate, to thus cause thelyophobic agent to adhere to the processing target surface, to thusproduce the lyophobic film 3.

In the print step, a method that enables linear supply of a lyophobicliquid, such as transfer printing, screen printing, dispensing, andinkjet printing, is employed. Specifically, as shown in FIG. 6, a liquidthat is to form the lyophobic film 3 is printed in a grid shape of thescribe lines 1 c to a print width “b” (about 20 micrometers) within arange of the width of each of the scribe lines 1 c set in considerationof a dicing margin having a separation width B (about 50 micrometers to60 micrometers). Moreover, a liquid that is to form a lyophobic film 3 eis printed in a circumferential pattern along the contour that is setalong the outer edge of the semiconductor wafer 1 to a predeterminedwidth corresponding to the print width “b.” At this time, an essentialrequirement for a widthwise position of the lyophobic film 3 is that thelyophobic film 3 should fall within a range of the separation width B ofeach of the scribe lines 1 c. Therefore, a widthwise positional error ofabout ±20 micrometers is allowed. A widthwise edge 3 a on either side ofthe lyophobic film 3 does not require a high degree of linear accuracy.Even when the edge exhibits a wavelike shape to some extent, the edgesdo not cause any problem. Likewise, the lyophobic film 3 e does notrequire a widthwise positional accuracy, either, and is allowed toexhibit a wavelike shape to some extent.

The lyophobic pattern formed along a periphery of the outer edge of thesemiconductor wafer 1 is now described in detail. As shown in FIG. 6, inrelation to the scribe lines 1 c (FIG. 4) that separate normalsemiconductor chips 1 e in the semiconductor wafer 1, the lyophobic film3 is orderly printed in a grid shape. On the contrary, the lyophobicfilm 3 is not always printed along the grid lines shown in FIG. 4 in thevicinity of a contour of the outer edge of the semiconductor wafer 1.Depending on a size of squares surrounded by inner lyophobic films 3 andthe lyophobic film 3 e of the contour, printing the lyophobic films 3 isomitted. Specifically, when the lyophobic pattern is formed by printingthe lyophobic films 3 along the grid lines and when areas of respectivesquares surrounded by the grid-like lyophobic films 3 and the lyophobicfilm 3 e of the outer edge are too small to efficiently apply a resin,printing the lyophobic films 3 along the grid lines corresponding toborders between the current square and adjoining squares is omitted tounite the square with the adjoining square.

In FIG. 5, in relation to much of outer edge squares 1R(1) to 1R(9)defined by areas surrounded by the lyophobic film 3 e formed along thecontour of the semiconductor wafer 1 and the lyophobic films 3 printedin grid lines, some of the lyophobic films 3 corresponding to the gridlines are omitted, and adjoining two squares unite with each other,thereby forming one square. As a result, areas [A1] to [A9] of therespective outer edge squares 1R(1) to 1R(9) do not much differ from anarea [A] of the normal semiconductor chip 1 e separated by the scribelines 1 c. Occurrence of excessive variations in required quantity ofliquid resin applied, which will be described later, can be prevented.Alternatively, it is also possible to calculate the area [A] of thesemiconductor chip 1 e and the respective areas [A1] to [A9] of theouter edge squares 1R(1) to 1R(9) in advance as numerical data and storethe data as application quantity data showing an appropriate quantity ofresin applied to each square.

After the print step, the semiconductor wafer 1 is sent to the bakingstep, where the wafer is heated to a temperature of the order of 40degrees centigrade to 50 degrees centigrade, whereby the lyophobic films3 whose lyophobic agent has adhered to the rear surface 1 b are formed.As shown in FIG. 7, a thickness t1 of the lyophobic films 3 comes to 0.1micrometers to 2 micrometers. When processing pertaining to the bakingstep is performed in a vacuum, a baking temperature can be reduced, sothat occurrence of an increase in print width “b” can be prevented. Ifthe solvent component evaporates during the print step, there will be noneed to perform processing pertaining to the baking step.

The semiconductor wafer 1 on which the lyophobic pattern has been formedas mentioned above comes to an objective of application of a liquidresin for mask formation. As mentioned previously, the resin is appliedin two steps; namely, the low viscosity resin (the second liquid)exhibiting superior wettability is previously applied in order to assurean appropriate spread of a high viscosity resin within the areassurrounded by the lyophobic films 3 before applying the high viscosityresin (the first liquid) including a resin, which is to make up a mask,in a solvent in a high concentration.

Any of hydrocarbon resins, which are not eliminated by plasma etchingperformed for the purpose of eliminating silicon—a material of thesemiconductor wafer 1—and which can be easily removed by plasma ashingintended for removing a mask later, is used for the resin (resist)included in the first liquid that is the high viscosity resin. A liquidsolution made by dissolving the resin in a saturated-hydrocarbon-basedsolvent is used as the first liquid. A composition of the first liquidis set such that a resin serving as solute assumes 40 to 80 percentcontent and that a solvent assumes 60 to 20 percent content. It ispreferable to set the resin content so as to fall within a range from 40to 50 percents.

The second liquid is set such that a resin (identical with the resinincluded in the first liquid) serving as solute assumes 0 to 40 percentcontent and that a solvent assumes 100 to 70 percent content. It ispreferable to set the resin content so as to fall within a range from 10to 20 percents. A purpose of application of the second liquid is tospread the second liquid in a wet fashion over the rear surface 1 b inorder to assure an appropriate spread of the high viscosity resin thatis the first liquid to be applied later. Therefore, the second liquiddoes not always need to include a resin as solute. As indicated by thecomposition mentioned above, the first liquid may also be formed from 0percent solute content and 100 percent solvent content.

When the second liquid includes a resin, the second liquid is a lowconcentration, low viscosity resin including a resin content that islower than that of the first liquid. When the second liquid does notinclude a resin, the second liquid is made of only a solvent. In anycase, the second liquid is lower than the first liquid in terms ofviscosity. The second liquid exhibits superior wettability required toassure an appropriate spread of the first liquid to be applied later.

Specifically, under the substrate processing method described inconnection with the embodiment, two types of liquids are prepared;namely, the first liquid including at least a solvent and a resin, andthe second liquid whose viscosity is lower than that of the firstliquid. Example configurations for making the viscosity of the secondliquid lower than the viscosity of the first liquid include a firstconfiguration for making the second liquid from solely a solvent and asecond configuration for making the concentration of the resin includedin the second liquid lower than the concentration of the resin includedin the first liquid. In the first and second configurations, the secondliquid includes the same solvent as that of the first liquid. In thesecond configuration, the second liquid includes the same resin as thatof the first liquid, and the concentration of the resin included in thesecond liquid is lower than the concentration of the resin included inthe first liquid.

For convenience's sake, a single type of solvent is used for the firstliquid and the second liquid. However, the solvent of the first liquiddoes not always need to be identical with the solvent of the secondliquid. A solvent of another type can also be used for the secondliquid, so long as the solvent has a property of being dissolved in thefirst liquid. Likewise, example configurations for making the viscosityof the second liquid lower than the viscosity of the first liquidinclude a third configuration for forming the second liquid from solelya solvent and a fourth configuration for making the concentration of theresin included in the second liquid lower than the concentration of theresin included in the first liquid. In the third and fourthconfigurations, the solvent of the second liquid differs in type fromthe solvent of the first liquid, and the solvent has a property of beingdissolved in the first liquid. In the fourth configuration, the resinincluded in the second liquid is identical with the resin included inthe first liquid. The concentration of the resin included in the secondliquid is lower than the concentration of the resin included in thefirst liquid.

The thus-prepared first and second liquids are supplied, in sequence ofthe second liquid and the first liquid, to the semiconductor wafer 1 onwhich the lyophobic pattern has been formed. An explanation is now givento a case where a low viscosity resin including a resin in a lowconcentration is used as the second liquid. First, as shown in FIG. 1,the low viscosity resin is applied (ST2). Specifically, as shown in FIG.2( b), a low viscosity resin 4 a (the second liquid) for the purpose ofmask formation is supplied to the rear surface 1 b that is theprocessing target surface of the semiconductor wafer 1 on which thelyophobic pattern is formed from the lyophobic films 3.

FIG. 8( a) shows a state in which a dispense nozzle 5A applies the lowviscosity resin 4 a. As mentioned previously, the low viscosity resin 4a squirted from the dispense nozzle 5A to a center position in an area Rsurrounded by the lyophobic films 3 on the rear surface 1 b spreads in awet fashion toward a periphery within the area R along the rear surface1 b. The low viscosity resin 4 a spread in a wet fashion is repelled bysurfaces of the lyophobic films 3 exhibiting a lyophobic property, tothus adhere to only the area devoid of the lyophobic films 3. At thistime, the low viscosity resin 4 a has low viscosity and exhibitssuperior wettability and, hence, reliably advances to positions adjacentto borders D between the lyophobic films 3 formed in a grid shape andthe area R. Further, the low viscosity resin 4 a also advances toindentations of corners C where the lyophobic films 3 cross each otherwithout causing gaps.

The high viscosity resin is now applied (ST3). As shown in FIG. 2( c),in addition to the low viscosity resin 4 a, a high viscosity resin 4 b(the first liquid) including a resin for mask formation in a highconcentration is applied to the rear surface 1 b of the semiconductorwafer 1 over which the low viscosity resin 4 a has already been applied.Specifically, as shown in FIG. 8( b), a dispense nozzle 5B squirts thehigh viscosity resin 4 b to the center of the area R on the rear surface1 b that is surrounded by the lyophobic films 3 and where the lowviscosity resin 4 a has already been applied. At this time, since acoating film of the low viscosity resin 4 a that is to be dissolved inthe high viscosity resin 4 b has already been formed over the entiretyof the area R, the squirted high viscosity resin 4 b spreads toward theperiphery within the area R while being dissolved in the low viscosityresin 4 a and also guided by the low viscosity resin 4 a. During thecourse of spread of the high viscosity resin 4 b, the concentration ofthe resin in the low viscosity resin 4 a and the concentration of theresin in the high viscosity resin 4 b become uniform.

The low viscosity resin 4 a and the high viscosity resin 4 b are therebymixed together, whereby a resin film 4 having a uniform concentration ofresin is produced. The resin film 4 is at this time repelled by thesurface of the lyophobic films 3 exhibiting a lyophobic property,thereby adhering to only areas devoid of the lyophobic films 3 andadvancing to positions where the films become close to the borders D.Further, the resin film enters the indentations of the corners C withoutcausing gaps. As shown in FIG. 8( c), the resin film 4 having athickness t2 (see FIG. 10) that is larger than the thickness t1 of thelyophobic films 3 (see FIG. 7) is formed in the area R surrounded by thelyophobic films 3. It is preferable that a composition of the resin film4 achieved when the low viscosity resin 4 a and the high viscosity resin4 b are completely mixed together should include 30% or more and,desirably, about 40% of a resin serving as solute. By adoption of such aresin content, the rein film 4 holds itself on the rear surface 1 bwithin the area R surrounded by the lyophobic films 3 in the course ofthe resin film 4 being heated, to thus evaporate the solvent. Therefore,the resin film 4 can sustain its shape in an applied state withoutcausing contraction of a two-dimensional shape.

Specifically, in the steps (ST2) and (ST3) where the previously preparedlow viscosity resin 4 a serving as the first liquid and the highviscosity resin 4 b serving as the second liquid are supplied to therear surface 1 b, which is the processing target surface of thesemiconductor wafer 1 on which the lyophobic pattern is formed, insequence of the high viscosity resin 4 b serving as the second liquidand the low viscosity resin 4 a serving as the first liquid. The resinfilm 4 whose thickness is larger than that of the lyophobic pattern isthereby formed in the area R that is surrounded by the lyophobic films 3and where the lyophobic pattern is not formed (a resin film formationstep).

Since the lyophobic film 3 e having the same lyophobic property as thatof the lyophobic films 3 is formed along the contour of thesemiconductor wafer 1 set along the outer edge of the semiconductorwafer 1 to a predetermined width, on the occasion of application of thelow viscosity resin 4 a and the high viscosity resin 4 b, the lowviscosity resin 4 a and the high viscosity resin 4 b squirted from therespective dispense nozzles 5A and 5B to the contour of thesemiconductor wafer 1 are repelled by the lyophobic film 3 e. Therefore,it is possible to prevent the low viscosity resin 4 a and the highviscosity resin 4 b from hanging and falling from the outer edge of thesemiconductor wafer 1, which would otherwise occur when the lyophobicfilm 3 e is not present, and also prevent staining of the wafer table,which would otherwise be cause by a drop of the resin.

In relation to application of the low viscosity resin 4 a from thedispense nozzle 5A and application of the high viscosity resin 4 b fromthe dispense nozzle 5B, a quantity of resin squirted from the dispensenozzle 5A and a quantity of resin squirted from the dispense nozzle 5Bmay also be controlled according to the area of the square surrounded bythe lyophobic films 3. Specifically, as has been described by referenceto FIG. 5, the quantity of resin squirted from the dispense nozzle 5Aand the quantity of resin squired from the dispense nozzle 5B arecontrolled according to application quantity data that specify for eachsquare an appropriate quantity of resin applied, in association with thearea [A] of the semiconductor chip 1 e and the areas [A1] to [A9] of theouter edge squares 1R(1) to 1R(9). A proportion of the quantity of thelow viscosity resin 4 a applied to the quantity of the high viscosityresin 4 b applied is set for each square in such a way that the quantityof the high viscosity resin 4 b applied falls within a range from two tofive, provided that the quantity of the low viscosity resin 4 a appliedis taken as one.

FIG. 9 shows, in an enlarged manner, a state of a contact between thelyophobic films 3 and the resin film 4 achieved after the resin filmformation step. Although the edges 3 a on both widthwise edges of eachof the lyophobic films 3 assume a minute wavelike shape (a saw-toothedshape), a contour 4 c of the resin film 4 (illustrated by broken linesin FIG. 9) remaining in contact with the edges 3 a forms asubstantially-linear, smooth line. The reason for this is that the resinfilm 4 exhibits surface tension in a liquid state and also a property ofbeing impervious to following minute irregularities of the respectiveedges 3 a because of action of surface tension. The property is veryadvantageous in view of formation of a mask having smooth edges. Whenthe resin film 4 having the smooth contour 4 c is treated in thesubsequent baking step, a mask having edges (smooth edges) correspondingto the contour 4 c is formed.

Subsequently, the thus-applied resin is dried (ST4). The semiconductorwafer 1 on which the resin film 4 is formed is again sent to the bakingstep, where the semiconductor wafer 1 is heated to a temperature rangingfrom 40 degrees centigrade to 70 degrees centigrade. As shown in FIG. 2(d), the solvent of the resin film 4 is vaporized, thereby forming, onthe rear surface 1 b that is the processing target surface (a maskformation step), a mask 4* that covers an area of the semiconductorwafer 1 except for the area (the area of the lyophobic films 3 set alongthe scribe lines 1 c) to be etched away by plasma processing (the maskformation step).

FIG. 10 is a cross sectional view of the resin film and the mask. Duringthe mask formation step, the solvent evaporates from the resin film 4,and a thickness t3 of the mask therefore becomes smaller than thethickness t2 of the resin film. For this reason, the thickness t3 of themask is adjusted by adjustment of the thickness t2 of the resin film 4;namely, setting the resin content in the low viscosity resin 4 a and theresin content in the high viscosity resin 4 b and controlling thequantity of the low viscosity resin 4 a applied and the quantity of thehigh viscosity resin 4 b applied. The required thickness t3 of the maskis determined in consideration of etch resistance and an ashing time. Inthe present embodiment, a preferred value of the thickness t3 rangesfrom 5 micrometers to 20 micrometers. A relationship (a contractionfactor) between the thickness t2 and the thickness t3 can be determinedby a test, or the like. Accordingly, the thickness t2 of the resin film4 required to obtain the required thickness t3 of the mask is determinedfrom the contraction factor and the thickness t3. When the thickness t2is determined, the resin content of the low viscosity resin 4 a, thequantity of low viscosity resin 4 a applied, the resin content of thehigh viscosity resin 4 b, and the quantity of high viscosity resin 4 bapplied, all of which are required to achieve the thickness t2, can bedetermined by calculation.

After the mask formation step, the lyophobic pattern is removed as shownin FIG. 2( e) (ST5). Specifically, there is performed processing fordissolving the lyophobic pattern formed from the lyophobic films 3 bymeans of a solvent, to thus eliminate the lyophobic pattern from therear surface 1 b that is the processing target surface (a lyophobicpattern removal step). Processing is performed by supplying a solvent,such as ketones, polyalcohols, cyclic ethers, lactones, and esters, tothe rear surface 1 b on which the mask has already been formed, therebydissolving the resin component of the lyophobic films 3 and eliminatingthe thus-dissolved films along with the solvent. A solvent that differslittle from the substance used for the lyophobic films 3 in terms of anSP value is chosen as the solvent to be used this time. Dipping, spinetching, spraying, or the like, can be used as a method for supplyingthe solvent to the rear surface 1 b, to thus remove the lyophobic films3.

Processing pertaining to the lyophobic pattern removal step can also beperformed by means of plasma etching using an oxygen gas plasma.Specifically, the semiconductor wafer 1 having undergone processingpertaining to the mask formation step is exposed in such a way that therear surface 1 b is irradiated with the oxygen gas plasma. The lyophobicfilms 3 and the mask 4*, which each are organic substances, areincinerated by ashing action of the oxygen gas plasma, to thus beremoved. However, the thickness t3 of the mask 4* is sufficiently largerthan the thickness t1 of the lyophobic films 3. Therefore, even afterthe lyophobic films 3 have been removed by ashing, the mask 4* stillremains in a sufficient thickness on the rear surface 1 b. Thus, themask 4* can fulfill its function as a mask for etching using plasma.

After the lyophobic pattern removal step, the semiconductor wafer 1 thatis a substrate is subjected to plasma etching (ST6). Specifically, thesemiconductor wafer 1 is etched for dicing by means of plasma processingfrom the rear surface 1 b that is the processing target surface of thesemiconductor wafer 1, until the protective sheet 2 becomes uncovered(an etching step). The semiconductor wafer 1 is sent to a plasmaprocessing apparatus, where the rear surface 1 b of the semiconductorwafer 1 is irradiated with a fluorine-based gas plasma P, such as SF6,(FIG. 2( f)). A portion of the rear surface 1 b of the semiconductorwafer 1, which is not covered with the mask 4* and exposed to the plasmaP, is removed by etching action of the plasma P, whereby an etchingtrench 1 d is formed. As a result of the etching trench 1 d penetratingthrough an entire thickness of the semiconductor wafer 1, whereupon thesemiconductor wafer 1 is separated into discrete semiconductor chips 1 eas shown in FIG. 2( f).

During etching using the plasma P, the mask 4* having smooth edges isformed. Consequently, a diced edge of each of the separated discretesemiconductor chips 1 e achieves a smooth, irregularity-free cutsurface. Therefore,

it is possible to prevent occurrence of a defect that would deterioratereliability of a semiconductor chip; in other words, a problem that islikely to arise when a cut surface has a rough shape, or minute cracksattributable to concentration of stress on minute irregularities.

The mask 4* is then removed (ST7). The semiconductor wafer 1 havingfinished undergoing processing pertaining to the etching step issubjected to processing for removing the mask 4* from the rear surface 1b that is the target processing surface (a mask removal step). Maskremoval is performed by means of ashing for incinerating and removingthe resin film 4 including a hydrocarbon-based resin as a component byuse of an oxygen gas plasma. As a matter of course, a method formechanically exfoliating the mask 4* from the rear surface 1 b or a wetmask removal method using a chemical can also be used during maskremoval. The semiconductor wafer 1 thereby enters a state in which thediscrete semiconductor chips 1 e are individually affixed to theprotective sheet 2 as shown in FIG. 2( g).

Subsequently, a die-bonding sheet 11 is affixed to the surface fromwhich the mask 4* has already been removed (ST8). As shown in FIG. 3(a), the semiconductor wafer 1 from which the mask has already beenremoved; namely, the plurality of semiconductor chips 1 e that each havethe circuit fabrication surfaces 1 a adhesively held by the protectivesheet 2, is transferred while the respective rear surfaces 1 b of therespective semiconductor chips 1 e are affixed to the die-bonding sheet11. The die-bonding sheet 11 is stretched to an annular wafer ring 12 a,to thus make up a wafer jig 12.

The protective sheet 2 is now removed (ST9). Specifically, theprotective sheet 2 is peeled off from the semiconductor chips 1 eaffixed to the die-bonding sheet 11. As shown in FIG. 3( b), thediscrete semiconductor chips 1 e exposed with their circuit fabricationsurfaces 1 e oriented upward are held, through the respective rearsurfaces 1 b, by the die-bonding sheet 11, thereby completing asemiconductor chip aggregate 10. The semiconductor chip aggregate 10 issent in this state to a die bonder. As shown in FIG. 3( c), the waferring 12 a is held by a wafer hold mechanism 13 of the die bonder,whereby the discrete semiconductor chip 1 e enters a state in which thechip can be picked up.

On the occasion of the picking-up of the semiconductor chip 1 e, abonding tool 14 and an ejector 15 are positioned to the semiconductorchip 1 e that is to be picked up. An ejector pin 16 provided on theejector 15 pushes the semiconductor chip 1 e to be taken out from below,and the bonding tool 14 picks up and holds the semiconductor chip 1 e.The bonding tool 14 has built-in heating means, and the semiconductorchip 1 e is heated to a predetermined temperature as a result of beingheld by the bonding tool 14.

The bonding tool 14 that holds the thus-picked-up semiconductor chip 1 etravels to a position above a heating support 17 that holds a substrate18 to be bonded. A die-bonding adhesive 19 is applied over the substrate18 in advance, and the substrate 18 is also heated in advance to apredetermined temperature by a heating mechanism (omitted from thedrawings) provided in the heating support 17. The semiconductor chip 1 eis aligned to a bonding position, and the bonding tool 14 is lowered,thereby placing the semiconductor chip 1 e on an upper surface of thesubstrate 18 by way of the adhesive 19. Next, the bonding tool 14presses the semiconductor chip 1 e against the substrate 18 underpredetermined applied pressure. Thermosetting reaction of the adhesive19 proceeds as a result of the substrate being held in this state for apredetermined period of time. The semiconductor chip 1 e is bonded tothe substrate 18 by means of the thermosetting adhesive 19.

As mentioned above, in the plasma dicing described in connection withthe first embodiment, the following method is employed during maskformation implemented by etching using plasma processing. Namely, themethod includes printing the lyophobic liquid on an area to be etched,thereby forming the lyophobic pattern from the lyophobic films 3;preparing two types of liquids; namely, the first liquid including atleast a solvent and a resin, and the second liquid whose viscosity islower than that of the first liquid; supplying the liquids, indescending sequence of the second liquid and the first liquid, to theprocessing target surface of the substrate over which the lyophobicpattern is already formed, thereby forming the resin film 4 that isthicker than the lyophobic pattern on the area where the lyophobicpattern is not formed; and processing the semiconductor wafer over whichthe resin film 4 is formed in the baking step, thereby forming the mask4* that covers an area of the semiconductor wafer except the area to beetched.

The lyophobic pattern produced under the foregoing method does not needa high degree of positional accuracy and shape accuracy. Therefore, themask can be formed at low cost by means of the existing technique usingsimple, in expensive facilities. Therefore, a mask for use in etchingusing plasma processing can be formed at low cost without use of ahigh-cost method, like photolithography and laser irradiation.

There is employed the method for applying two types of liquids; namely,the first liquid including a solvent and a resin and the second liquidwhose viscosity is lower than that of the first viscosity, inpredetermined sequence, to thus form the resin film 4 for maskformation. As a result, it is possible to effectively prevent occurrenceof the following problems, which would otherwise be likely to ariseduring formation of a mask using a lyophobic pattern. Specifically, whena high viscosity liquid resin is used, wet-spreading of the resin ishindered by surface tension of the resin, thereby posing difficulty inletting the resin enter the corners of the lyophobic pattern withoutcasing gaps. Thus, it is difficult to form a mask assuming anappropriate shape. When a low viscosity liquid resin is used, superiorwettability is achieved in an applied state, and uniform application ofthe resin is possible. However, occurrence of contractive deformation ofa resin film, which would otherwise be caused by evaporation of thesolvent in the baking step subsequent to resin application, isunavoidable, thereby likewise posing difficulty in forming a mask havingan appropriate shape.

On the contrary, there is adopted the method for using two types ofliquids and first supplying the second liquid and the first liquid. As aresult, the second liquid can be uniformly spread in a wet fashionwithin an area surrounded by the lyophobic pattern. Next, the firstliquid, or the high viscosity resin, is supplied, whereby the firstliquid can be well spread in a wet fashion while being guided in thesecond liquid that has already been applied. Therefore, the problem isdissolved, and the resin film 4 for mask formation can be formed in asuperior shape.

Second Embodiment

A second embodiment of the present invention relates to a semiconductorchip manufacturing method utilizing an application of the substrateprocessing method described in connection with the first embodiment. Aresin adhesive layer used when the discrete semiconductor chips formedby separating the semiconductor chips are bonded is caused to act as amask required during etching operation using plasma processing forseparating the semiconductor wafer. In FIGS. 12 through 15, elementshaving configurations similar to those of their counterparts describedin connection with the first embodiment are assigned the same referencenumerals, and different reference numerals are assigned to solelyelement having different configurations, to thus be distinguished.

First, a lyophobic pattern and a resin adhesive layer of the presentembodiment are described. In the present embodiment, a lyophobic patternis formed from a resin (a lyophobic agent) that exhibits a lyophobicproperty against a solvent included in a liquid resin which is to act asa material for making up a resin adhesive layer. Specifically, thelyophobic pattern is formed, in advance, from a lyophobic agent in anarea except for an area on the semiconductor wafer where the resinadhesive layer is formed. The liquid resin making up the resin adhesivelayer is caused to adhere to solely the area where the resin adhesivelayer is to be formed. On the occasion of formation of the lyophobicpattern, a liquid (a lyophobic liquid) made by dissolving a lyophobicagent in a solvent is printed in a predetermined pattern by means oftransfer printing, screen printing, dispensing, inkjet printing, or thelike. A solvent component is volatized after printing, whereupon thelyophobic pattern is completed.

Thermosetting resins, such as epoxy-based resins, are used as a resinmaking up a resin adhesive layer. On the occasion of formation of aresin adhesive layer, a liquid resin made by dissolving a thermosettingresin in a solvent is applied over the processing target surface of thesubstrate over which the lyophobic pattern is formed, by means of amethod, like dispensing, inkjet printing, and spin-coating. Since thesolvent of the liquid resin applied over the processing target surfaceis repelled by the lyophobic agent, the liquid resin spreads over onlyan area of the processing target surface except for the lyophobicpattern. The substrate over which the liquid resin is applied is heated,thereby vaporizing the solvent. Further, the thermosetting resin issemi-cured, whereby a resin adhesive layer patterned by the lyophobicpattern is produced.

In the present invention adopting such a resin adhesive layer formationmethod, the lyophobic agent used for the lyophobic pattern mustcorrespond to a combination of lyophobic agents that exhibit a lyophobicproperty against the solvent included in the liquid resin used forforming a resin adhesive layer. In addition, a solvent that is dissolvedin a thermosetting resin must be chosen. Accordingly, when a resin to beused is any of epoxy-based thermosetting resins (having an SP value of10.9), any of alcohol-based solvents having an SP value ranging from10.0 to 11.9 is chosen as a solvent. Acrylic resins (having an SP valueof 9.2), silicone-based resins (having an SP value of 7.0), andfluorine-based resins (having an SP value of 3.6) can be used as alyophobic agent in this case.

Even in the second embodiment, during the course of the resin adhesivelayer being formed from liquid resins, two types of liquids havingdifferent viscosity levels are prepared, and the liquids are supplied intwo steps in the same manner as in the first embodiment. Specifically, alow viscosity resin (the second liquid) whose viscosity is lower than ahigh viscosity resin is first supplied before supplying the highviscosity resin (the first liquid) including a resin component which isto make up the resin adhesive layer in a high concentration. The lowviscosity resin is uniformly spread in a wet fashion within the areasurrounded by the lyophobic pattern, and the high viscosity resin isthen supplied, thereby assuring a quantity of resin component requiredto form a resin adhesive layer.

A resin-adhesive-layer-backed semiconductor chip manufacturing method isnow described by reference to the drawings; namely, a flowchart of FIG.11 and explanatory process charts of FIGS. 12 and 13. In FIG. 11, alyophobic pattern is first made over the semiconductor wafer 1 servingas a substrate (ST11). As shown in FIG. 12( a), a plurality ofsemiconductor chips including integrated circuits (semiconductordevices) are fabricated on the semiconductor wafer 1. The protectivesheet 2 for protecting the integrated circuits is affixed to the circuitfabrication surface 1 a of the semiconductor wafer 1 where theintegrated circuits are fabricated. The rear surface 1 b that is theother side of the circuit fabrication surface 1 a is made thin to athickness of 100 micrometers or less by means of removing a surfacelayer in a thinning step, which is a preceding step, through performanceof mechanical grinding.

Next, as shown in FIG. 12( b), a lyophobic pattern is formed, on therear surface 1 b (corresponding to the processing target surface of thesubstrate to be etched in the substrate), along the grid lines(corresponding to areas to be etched away) corresponding to the scribelines 1 c (see FIG. 4) that separate the semiconductor wafer 1 into therespective semiconductor chips 1 e and along the contour [see FIG. 2( a)and the lyophobic film 3 e shown in FIG. 5] set to a predetermined widthalong the outer edge of the semiconductor wafer 1 (the lyophobic patternformation step). In addition to being formed along the grid linescorresponding to the scribe lines 1 c (see FIG. 4), the lyophobicpattern is formed along the contour of the semiconductor wafer 1. Thelyophobic pattern formed along the contour is intended to prevent theliquid resin from running over the outer edge of the semiconductor wafer1 to thereby fall from the wafer, which would otherwise occur when theliquid resin is applied after formation of the lyophobic pattern. Thelyophobic pattern formation step is analogous to that described inconnection with the first embodiment, and hence its detailed explanationis omitted here for brevity.

The semiconductor wafer 1 on which the lyophobic pattern has been formedas mentioned above comes to an objective of application of a liquidresin for making a resin adhesive layer. As mentioned previously, theresin is applied in two steps; namely, the low viscosity resin (thesecond liquid) exhibiting superior wettability is applied in advance inorder to assure an appropriate spread of the high viscosity resin withinthe areas surrounded by the lyophobic films 3 before applying the highviscosity resin (the first liquid) including a resin, which is to makeup a mask, in a solvent in a high concentration.

Any of thermosetting resins, such as epoxy-based resins, is used for theresin to be included in the first liquid that is the high viscosityresin. A solution made by dissolving the thermosetting resin in analcohol-based solvent is used as the first liquid. A composition of thefirst liquid is set such that a resin serving as solute assumes 40 to 80percent content and that a solvent assumes 60 to 20 percent content. Itis preferable to set the resin content so as to fall within a range from40 to 50 percents.

The second liquid is also set such that a resin (identical with theresin included in the first liquid) serving as solute assumes 0 to 40percent content and that a solvent assumes 100 to 70 percent content. Itis preferable to set the resin content so as to fall within a range from10 to 20 percents. A purpose of application of the second liquid is tospread the second liquid over the rear surface 1 b in a wet fashion inorder to assure an appropriate spread of the high viscosity resin thatis the first liquid to be applied later. Therefore, the second liquiddoes not always need to include a resin as solute. As indicated by thecomposition mentioned above, the first liquid may also be formed from 0percent solute content and 100 percent solvent content.

When the second liquid includes a resin, the second liquid is a lowconcentration, low viscosity resin including a resin content that islower than that of the first liquid. When the second liquid does notinclude a resin, the second liquid is made of only a solvent. In anycase, the second liquid is lower than the first liquid in terms ofviscosity. The second liquid exhibits superior wettability required toassure an appropriate spread of the first liquid to be applied later.

Specifically, under the resin-adhesive-layer-backed semiconductor chipmanufacturing method described in connection with the embodiment, twotypes of liquids are prepared; namely, the first liquid including atleast a solvent and a resin, and the second liquid whose viscosity islower than that of the first liquid. Example configurations for makingthe viscosity of the second liquid lower than the viscosity of the firstliquid include the first configuration for making the second liquid fromsolely a solvent and the second configuration for making theconcentration of the resin included in the second liquid lower than theconcentration of the resin included in the first liquid. In the firstand second configurations, the second liquid includes the same solventas that of the first liquid. In the second configuration, the secondliquid includes the same resin as that of the first liquid, and theconcentration of the resin included in the second liquid is lower thanthe concentration of the resin included in the first liquid.

For convenience's sake, a single type of solvent is used for the firstliquid and the second liquid. However, the solvent of the first liquiddoes not always need to be identical with the solvent of the secondliquid. A solvent of another type can also be used for the secondliquid, so long as the solvent has a property of being dissolved in thefirst liquid. Likewise, example configurations for making the viscosityof the second liquid lower than the viscosity of the first liquidinclude the third configuration for forming the second liquid fromsolely a solvent and the fourth configuration for making theconcentration of the resin included in the second liquid lower than theconcentration of the resin included in the first liquid. In the thirdand fourth configurations, the solvent of the second liquid differs intype from the solvent of the first liquid, and the solvent has aproperty of being dissolved in the first liquid. In the fourthconfiguration, the resin included in the second liquid is identical withthe resin included in the first liquid. The concentration of the resinincluded in the second liquid is lower than the concentration of theresin included in the first liquid.

The thus-prepared first and second liquids are supplied, in sequence ofthe second liquid and the first liquid, to the semiconductor wafer 1 onwhich the lyophobic pattern has been formed. An explanation is now givento a case where a low viscosity resin including a resin in a lowconcentration is used as the second liquid. First, as shown in FIG. 11,the low viscosity resin is applied (ST12). Specifically, as shown inFIG. 12( b), a low viscosity resin 40 a (the second liquid) for thepurpose of mask formation is supplied to the rear surface 1 b that isthe processing target surface of the semiconductor wafer 1 on which thelyophobic pattern is formed from the lyophobic films 3. The highviscosity resin is now applied (ST13). As shown in FIG. 12( c), inaddition to the low viscosity resin 40 a, a high viscosity resin 40 b(the first liquid) including a resin for mask formation in a highconcentration is applied to the rear surface 1 b of the semiconductorwafer 1 over which the low viscosity resin 40 a has already beenapplied.

Specifically, in the steps (ST12) and (ST13) where the previouslyprepared low viscosity resin 40 a serving as the first liquid and thehigh viscosity resin 40 b serving as the second liquid are supplied tothe rear surface 1 b, which is the processing target surface of thesemiconductor wafer 1 on which the lyophobic pattern is formed, insequence of the high viscosity resin 40 b serving as the second liquidand the low viscosity resin 40 a serving as the first liquid. The resinfilm 40 whose thickness is larger than the thickness t1 of the lyophobicpattern is thereby formed in the area R that is surrounded by thelyophobic films 3 and where the lyophobic pattern is not formed (theresin film formation step). Details about application of the lowviscosity resin 40 a and the high viscosity resin 40 b performed in(ST12) and (ST13) are the same as those described in connection with thelow viscosity resin 4 a and the high viscosity resin 4 b in the firstembodiment by reference to FIG. 8, and hence their explanations areomitted here for brevity.

The lyophobic film 3 e having the same lyophobic property as that of thelyophobic films 3 is formed along the contour of the semiconductor wafer1 set along the outer edge of the semiconductor wafer 1 to apredetermined width. Hence, on the occasion of application of the lowviscosity resin 40 a and the high viscosity resin 40 b, the lowviscosity resin 40 a and the high viscosity resin 40 b squirted from therespective dispense nozzles 5A and 5B to the contour of thesemiconductor wafer 1 are repelled by the lyophobic film 3 e.Consequently, it is possible to prevent the low viscosity resin 40 a andthe high viscosity resin 40 b from hanging and falling from the outeredge of the semiconductor wafer 1, which would otherwise occur when thelyophobic film 3 e is not present, and also prevent staining of thewafer table, which would otherwise be cause by a drop of the resin.

In relation to application of the low viscosity resin 40 a from thedispense nozzle 5A and application of the high viscosity resin 40 b fromthe dispense nozzle 5B, a quantity of resin squirted from the dispensenozzle 5A and a quantity of resin squirted from the dispense nozzle 5Bmay also be controlled according to the area of the square surrounded bythe lyophobic films 3. Specifically, as has been described by referenceto FIG. 5, the quantity of resin squirted from the dispense nozzle 5Aand the quantity of resin squired from the dispense nozzle 5B arecontrolled according to application quantity data that specify for eachsquare an appropriate quantity of resin applied, in association with thearea [A] of the semiconductor chip 1 e and the areas [A1] to [A9] of theouter edge squares 1R(1) to 1R(9). A proportion of the quantity of thelow viscosity resin 40 a applied to the quantity of the high viscosityresin 40 b applied is set for each square in such a way that thequantity of the high viscosity resin 40 b applied falls within a rangefrom two to five, provided that the quantity of the low viscosity resin40 a applied is taken as one.

FIG. 14 shows, in an enlarged manner, a state of a contact between thelyophobic films 3 and the resin film 40 achieved after the resin filmformation step. Although the edges 3 a on both widthwise edges of eachof the lyophobic films 3 assume a minute wavelike shape (a saw-toothedshape), a contour 40 c of the resin film 40 (illustrated by broken linesin FIG. 14) remaining in contact with the edges 3 a forms asubstantially-linear, smooth line. The reason for this is that the resinfilm 40 exhibits surface tension in a liquid state and also a propertyof being impervious to following minute irregularities of the respectiveedges 3 a because of action of surface tension. The property is veryadvantageous in view of formation of a mask having smooth edges. Whenthe resin film 4 having the smooth contour 40 c is treated in thesubsequent baking step, a mask having edges (smooth edges) correspondingto the contour 40 c is formed.

Subsequently, the thus-applied resin is semi-cured (ST14). Thesemiconductor wafer 1 on which the resin film 40 is formed is again sentto a curing step, where the semiconductor wafer 1 is heated to atemperature of about 90 degrees centigrade. The resin film 40 isthus-semi-cured in a state of B stage, whereby a resin adhesive layer40* is formed as shown in FIG. 12( d) (a resin adhesive formation step).At this time, the resin adhesive layer 40* covers an area except for thearea to be removed by means of etching using plasma processing (i.e.,the area of the lyophobic films 3 set along the scribe lines 1 c).Therefore, the resin adhesive layer 40* acts as a mask for etching usingplasma processing. The thickness of the resin adhesive layer 40* isreduced from the shape of the adhesive layer achieved after applicationby an amount equal to the quantity of evaporated solvent.

FIG. 15 is a cross sectional view of the resin film 40 and the resinadhesive layer 40*. Since the solvent evaporates from the resin film 40in the resin adhesive layer formation step, a thickness t5 of the resinadhesive layer 40* becomes smaller than a thickness t4 of the resin film40. Therefore, adjustment of the thickness t5 of the adhesive resinlayer 40* is adjusted by adjustment of the thickness t4 of the resinfilm 40; namely, setting the resin content in the low viscosity resin 40a and the resin content in the high viscosity resin 40 b and controllingthe quantity of the low viscosity resin 40 a applied and the quantity ofthe high viscosity resin 40 b applied. The required thickness t5 of theresin adhesive layer 40* is determined from the thickness of thesemiconductor chip 1 e that is an objective of bonding, the thickness ofthe adhesive layer achieved after bonding, and the like.

In the present embodiment, a value of the thickness t5 is determinedfrom the thickness of an adhesive layer to which the semiconductor chip1 e is to be die-bonded, and the value of the thickness t5 preferablyranges from 20 micrometers to 30 micrometers. A relationship (acontraction factor) between the thickness t4 and the thickness t5 can bedetermined by a test, or the like. Accordingly, the thickness t4 of theresin film 40 required to obtain the required thickness t5 of the resinadhesive resin layer 40* is determined from the contraction factor andthe thickness t5. When the thickness t4 is determined, the resin contentof the low viscosity resin 4 a, the quantity of low viscosity resin 40 aapplied, the resin content of the high viscosity resin 40 b, and thequantity of high viscosity resin 40 b applied, all of which are requiredto achieve the thickness t4, can be determined by calculation.

After the resin adhesive layer formation step, the lyophobic pattern isremoved as shown in FIG. 12( e) (ST15). Specifically, there is performedprocessing for dissolving the lyophobic pattern formed from thelyophobic films 3 by means of a solvent, to thus eliminate the lyophobicpattern from the rear surface 1 b (the lyophobic pattern removal step).Processing is identical with processing pertaining to the lyophobicpattern removal step described in connection with the first embodiment,and hence its explanation is omitted here for brevity.

After the lyophobic pattern removal step, the semiconductor wafer 1 thatis a substrate is subjected to plasma etching (ST16). Specifically, thesemiconductor wafer 1 is etched for dicing by means of plasma processingfrom the rear surface 1 b that is the processing target surface of thesemiconductor wafer 1, until the protective sheet 2 becomes uncovered(the etching step). The semiconductor wafer 1 is sent to a plasmaprocessing apparatus, where the rear surface 1 b of the semiconductorwafer 1 is irradiated with a fluorine-based gas plasma P, such as SF6,(FIG. 12( f)). A portion of the rear surface 1 b of the semiconductorwafer 1, which is not covered with the resin adhesive layer 40* servingas the mask and exposed to the plasma P, is removed by etching action ofthe plasma P, whereby the etching trench 1 d is formed. As a result ofthe etching trench 1 d penetrating through an entire thickness of thesemiconductor wafer 1, whereupon the semiconductor wafer 1 is separatedinto discrete semiconductor chips 1 e as shown in FIG. 12( f). Aftercompletion of processing pertaining to the etching step, thesemiconductor wafer 1 to which there is affixed the protective sheet 2for protecting the circuit fabrication surface 1 a is separated into aplurality of semiconductor chips 1 f, each of which has the resinadhesive layer 40* in the state of B stage placed on the rear surface 1b of the semiconductor chip 1 e for use in die-bonding operation.

During etching using the plasma P, heat of the plasma P exerts on theresin adhesive layer 40*. As mentioned previously, the resin adhesivelayer 40* is required to hold a semi-cured state of B stage. Hence, inthe course of plasma processing, temperature conditions are required tobe controlled such that a surface temperature of the resin adhesivelayer 40* does not exceed a thermosetting temperature (100 degreescentigrade to 150 degrees centigrade) of a chosen epoxy-based resin. Amethod used for controlling the temperature conditions includesappropriately adjusting plasma processing conditions of a plasmaprocessing apparatus used; for instance, appropriate adjustment of anoutput from a high frequency power unit, or controlling a temperature ofthe semiconductor wafer 1 by use of cooling means for circulating acooling medium through an interior of electrodes where the semiconductorwafer 1 to be processed is placed, to thus prevent the temperature ofthe semiconductor wafer 1 from rising in excess of an appropriate range.A configuration for the plasma processing apparatus that circulates thecooling medium through the interior of the electrodes where a processingtarget is placed in order to prevent excessive heating of the processingtarget is a known technique (see; for instance, JP-A-2004-55703 andJP-A-2007-80912).

During plasma dicing, the adhesive resin layer 40*(a mask) having smoothedges is formed. Consequently, a diced edge of each of the separateddiscrete semiconductor chips 1 e also achieves a smooth,irregularity-free cut surface. Therefore, it is possible to preventoccurrence of a defect that would deteriorate reliability of asemiconductor chip; in other words, a problem that is likely to arisewhen a cut surface has a rough shape, or minute cracks attributable toconcentration of stress on minute irregularities.

Subsequently, the die-bonding sheet 11 is affixed to the resin adhesivelayer 40* (ST17). As shown in FIG. 13( a), the plurality ofsemiconductor chips 1 f with adhesive resin layers whose circuitfabrication surfaces 1 a are held and affixed to the protective sheet 2are transferred while the respective resin adhesive layers 40* areaffixed to the die-bonding sheet 11. The die-bonding sheet 11 isstretched to the annular wafer ring 12 a, to thus make up the wafer jig12.

The protective sheet 2 is now removed (ST18). Specifically, theprotective sheet 2 is peeled off from the semiconductor chip 1 f with aresin adhesive layer affixed to the die-bonding sheet 11. As shown inFIG. 13( b), the semiconductor chip aggregate 10 is completed, whereinthe plurality of semiconductor chips if with resin adhesive layers,whose circuit fabrication surfaces 1 a are oriented upward and exposed,are held by the die-bonding sheet 11 from the respective rear surfaces 1b. The semiconductor chip aggregate 10 is sent in this state to a diebonder. As shown in FIG. 3( c), the wafer ring 12 a is held by the waferhold mechanism 13 of the die bonder, whereby the discrete semiconductorchip 1 f enters a state in which the discrete semiconductor chip 1 witha resin adhesive layer can be picked up.

On the occasion of the picking-up of the semiconductor chip 1 f with theresin adhesive layer, the die-bonding tool 14 and the ejector 15 arepositioned to the semiconductor chip 1 f with the resin adhesive layerthat is to be picked up. The ejector pin 16 provided on the ejector 15pushes the semiconductor chip 1 f with the resin adhesive layer to betaken out from below, and the bonding tool 14 picks up and holds thesemiconductor chip 1 f with the resin adhesive layer. The bonding tool14 has built-in heating means, and the semiconductor chip 1 f with theresin adhesive layer is heated to a predetermined temperature as aresult of being held by the bonding tool 14.

The bonding tool 14 that holds the thus-picked-up semiconductor chip 1 fwith the resin adhesive layer travels to a position above the heatingsupport 17 that holds the substrate 18 to be bonded. The substrate 18 isalso heated in advance to a predetermined temperature by a heatingmechanism (omitted from the drawings) provided in the heating support17. The semiconductor chip 1 f with the resin adhesive layer is alignedto a bonding position, and the bonding tool 14 is lowered, therebyplacing the semiconductor chip 1 e on the upper surface of the substrate18 by way of the resin adhesive layer 40*. Next, the bonding tool 14presses the semiconductor chip 1 e against the substrate 18 underpredetermined applied pressure. Thermosetting reaction of the resinadhesive layer 40* proceeds as a result of the substrate being held inthis state for a predetermined period of time. The semiconductor chip 1e is bonded to the substrate 18 by means of the resin adhesive layer40*.

As mentioned above, in the second embodiment, during manufacture ofsemiconductor chips for separating the semiconductor wafer 1 into thesemiconductor chips if with adhesive resin layers, which each are formedfrom semiconductor devices, by means of etching using plasma processing,there is employed a method including printing a lyophobic liquid on therear surface 1 b of the semiconductor wafer 1 that is the other side ofthe circuit fabrication surface 1 a, along the scribe lines 1 c that areborders between the semiconductor chips 1 e, thereby forming a lyophobicpattern; preparing two types of liquids; namely, the first liquidincluding at least a solvent and a resin, and the second liquid whoseviscosity is lower than that of the first liquid; supplying the liquidsover the processing target surface of the semiconductor wafer 1 wherethe lyophobic pattern is formed, in descending sequence of the secondliquid and the first liquid, thereby forming the resin film 40 that isthicker than the lyophobic pattern is formed on the area where thelyophobic pattern is not formed; semi-curing the resin film 40, to thusform the resin adhesive layer 40*; and etching, after removal of thelyophobic pattern from the rear surface of the semiconductor wafer, therear surface 1 b of the semiconductor wafer 1 while the resin adhesivelayer 40* is taken as a mask. As a result, a mask for etching usingplasma processing is formed at low cost, and the mask can also be usedas the resin adhesive layer 40* for die-bonding. Further, the advantageyielded when the two types of liquids are prepared and applied in twosteps as mentioned in connection with the resin film formation step isalso the same as that yielded in the first embodiment.

In the first and second embodiments, processing for separating thesemiconductor wafer serving as the substrate into discrete semiconductorchips by means of plasma dicing has been described as an exampleobjective of the invention. However, the present invention is notlimited to the processing. The present invention can be applied toprocessing of any form, so long as processing is intended for asubstrate and requires formation of a mask in association with etchingusing plasma processing. For instance, the present invention can beapplied to various types of processing intended for a substrate; forinstance, an example application for boring via holes in a semiconductorsubstrate by means of etching using a plasma, an example application forforming a minute mechanical device by application of a semiconductorprocessing technique and through use of etching using a plasma in acourse of manufacture of an MEMS (Microelectromechanical System); anexample application for forming a circuit pattern on a transparentdisplay panel; and the like.

The present patent application is based on Japanese Patent Application(JP-2009-095800) filed on Apr. 10, 2009, the entire subject matter ofwhich is incorporated herein by reference.

INDUSTRIAL APPLICABILITY

The substrate processing method and the semiconductor chip manufacturingmethod of the present invention are characterized in that a mask for usein etching using a plasma can be formed at low cost. The methods areuseful for processing various substrates, such as processing forseparating a semiconductor wafer serving as a substrate into discretesemiconductor chips, by means of plasma dicing.

DESCRIPTIONS OF THE REFERENCE NUMERALS AND SYMBOLS

-   -   1 SEMICONDUCTOR WAFER    -   1 a CIRCUIT FABRICATION SURFACE    -   1 b REAR SURFACE (PROCESSING TARGET SURFACE)    -   1 c SCRIBE LINE    -   1 e SEMICONDUCTOR CHIP    -   2 PROTECTIVE SHEET    -   3, 3 e LYOPHOBIC FILM    -   4 RESIN FILM    -   4 a LOW VISCOSITY RESIN (SECOND LIQUID)    -   4 b HIGH VISCOSITY RESIN (FIRST LIQUID)    -   4* MASK    -   40 RESIN FILM    -   40 a LOW VISCOSITY RESIN (SECOND LIQUID)    -   40 b HIGH VISCOSITY RESIN (FIRST LIQUID)    -   40* RESIN ADHESIVE LAYER    -   P PLASMA

1. A substrate processing method for partially eliminating a substrateby etching using plasma processing, the method comprising: a lyophobicpattern formation step of printing a lyophobic liquid to an area to beetched away on a processing target surface of the substrate, therebyforming a lyophobic pattern; a resin film formation step of preparing afirst liquid including at least a solvent and a resin and a secondliquid whose viscosity is lower than a viscosity of the first liquid andsupplying the liquids in descending sequence of the second liquid andthe first liquid on the processing target surface of a substrate onwhich the lyophobic pattern is formed, thereby forming a resin film thatis thicker than the lyophobic pattern in an area where the lyophobicpattern is not formed; a mask formation step of curing the resin film,to thus form on the processing target surface a mask for covering anarea except for the area to be etched away; a lyophobic pattern removalstep of removing the lyophobic pattern from the processing targetsurface after performance of processing pertaining to the mask formationstep; an etching step of etching the substrate from the processingtarget surface thereof using plasma processing after processingpertaining to the lyophobic pattern removal step; and a mask removalstep of removing the mask from the processing target surface aftercompletion of processing pertaining to the etching step.
 2. Thesubstrate processing method according to claim 1, wherein the secondliquid includes the same solvent as that of the first liquid.
 3. Thesubstrate processing method according to claim 2, wherein the secondliquid includes the same resin as that of the first liquid, and theresin in the second liquid is lower in concentration than the resin inthe first liquid.
 4. The substrate processing method according to claim1, wherein the second liquid includes a liquid that differs in type froma solvent of the first liquid and that exhibits a property of beingdissolved in the first liquid.
 5. A semiconductor chip manufacturingmethod for separating a semiconductor wafer, which has a plurality ofsemiconductor devices on a circuit fabrication surface and which isaffixed with a protective sheet for protecting the circuit fabricationsurface by means of etching using plasma processing, into semiconductorchips made up of respective semiconductor devices, the methodcomprising: a lyophobic pattern formation step of printing a lyophobicliquid on scribe lines serving as borders between semiconductor chips ona processing target surface of the semiconductor wafer that is anotherside of the circuit fabrication surface, thereby forming a lyophobicpattern; a resin film formation step of preparing a first liquidincluding at least a solvent and a resin and a second liquid whoseviscosity is lower than a viscosity of the first liquid and supplyingthe liquids in descending sequence of the second liquid and the firstliquid on the processing target surface of the substrate on which thelyophobic pattern is formed, thereby forming a resin film that isthicker than the lyophobic pattern in an area where the lyophobicpattern is not formed; a mask formation step of curing the resin film,to thus form on the processing target surface a mask for covering anarea except for the are to be etched away; a lyophobic pattern removalstep of removing the lyophobic pattern from the processing targetsurface after performance of processing pertaining to the mask formationstep; an etching step of etching the semiconductor wafer from theprocessing target surface thereof until the protective sheet becomesexposed on the processing target surface, after processing pertaining tothe lyophobic pattern removal step; and a mask removal step of removingthe mask from the processing target surface after completion ofprocessing pertaining to the etching step.
 6. The semiconductor chipmanufacturing method according to claim 5, wherein the second liquidincludes the same solvent as that of the first liquid.
 7. Thesemiconductor chip manufacturing method according to claim 6, whereinthe second liquid includes the same resin as that of the first liquid,and the resin in the second liquid is lower in concentration than theresin in the first liquid.
 8. The semiconductor chip manufacturingmethod according to claim 5, wherein the second liquid includes a liquidthat differs in type from a solvent of the first liquid and thatexhibits a property of being dissolved in the first liquid.
 9. Aresin-adhesive-layer-backed semiconductor chip manufacturing method formanufacturing semiconductor chips having on rear surfaces resin adhesivelayers for die-bonding purpose by means of plasma dicing for separatinga semiconductor wafer, which has a plurality of semiconductor devices ona circuit fabrication surface and which is affixed with a protectivesheet for protecting the circuit fabrication surface, into respectivesemiconductor devices by means of etching using plasma processing, themethod comprising: a lyophobic pattern formation step of printing alyophobic liquid on scribe lines serving as borders betweensemiconductor chips on a rear surface of the semiconductor wafer that isanother side of the circuit fabrication surface, thereby forming alyophobic pattern; a resin film formation step of preparing a firstliquid including at least a solvent and a resin and a second liquidwhose viscosity is lower than a viscosity of the first liquid andsupplying the liquids in descending sequence of the second liquid andthe first liquid on the processing target surface of the substrate onwhich the lyophobic pattern is formed, thereby forming a resin film thatis thicker than the lyophobic pattern in an area where the lyophobicpattern is not formed; a resin adhesive layer formation step ofsemi-curing the resin film, to thus form a resin adhesive layer; alyophobic pattern removal step of removing the lyophobic pattern fromthe rear surface after performance of processing pertaining to the resinadhesive layer formation step; and an etching step of etching, afterperformance of processing pertaining to the lyophobic pattern removalstep, the semiconductor wafer from the rear surface thereof while theresin adhesive layer is taken as a mask until the protective sheetbecomes exposed on the rear surface.
 10. The resin-adhesive-layer-backedsemiconductor chip manufacturing method according to claim 9, whereinthe second liquid includes the same solvent as that of the first liquid.11. The resin-adhesive-layer-backed semiconductor chip manufacturingmethod according to claim 10, wherein the second liquid includes thesame resin as that of the first liquid, and the resin in the secondliquid is lower in concentration than the resin in the first liquid. 12.The resin-adhesive-layer-backed semiconductor chip manufacturing methodaccording to claim 9, wherein the second liquid includes a liquid thatdiffers in type from a solvent of the first liquid and that exhibits aproperty of being dissolved in the first liquid.